Dr900

The research team ensured that the collected samples are analyzed within the same day of collection. Chemical parameters were mainly measured using the combination of spectrophotometer (Hach DR3900, HACH/LANGE, Berlin, Germany), colorimeter (Hach DR900, HACH/LANGE, Berlin, Germany), with standard reagents as well as the test kits provided by Hach Company, [31 ]. The Standard Operating Procedure for GLNPO Turbidity (The U.S. Environmental Protection Agency Great Lakes National Program Office, Washington, D.C.) was used for the analysis of turbidity [32 ], and the American Public Health Association (APHA) 4500-Nor, Washington, D.C., United States, was used for the analysis of total phosphorous, while lab pH-meter (Hach Co, HACH/LANGE, Berlin, Germany) was used for pH as well as the ultraviolet-visible (UV-V) spectrophotometer (PE-5400UV) pr-in ECOCHEMICAL, St. Petersburg, Russia was used for color measurements. The TSS in the samples was determined using Hach TSS portable hand-held turbidity meter. In general, the analyses of all the studied samples were accomplished following the recommendations in the APHA Standard Methods for the Examination of Water and Wastewater [33 ].

Measurements of nitrates and ammonia salts were performed using the Hach-DR900 multiparametric portable colorimeter. The residual fluid obtained from the filtration in the A. platensis biomass extraction process was used to perform the corresponding quantifications. The concentration (g L⁻¹) of nitrates was measured using method 8039 or the cadmium reduction method [19 ], and the concentration (g L⁻¹) of ammonia salts was measured using method 8155 or the salicylate method [20 ] from the Hach-DR900 procedures guide.

All water samples were filtered using a 0.45 µm filter (PALL, China) before the determination of NO₃⁻-N, and NO₂⁻-N. The concentrations of COD, TN, TP, NO₃⁻-N, and NO₂⁻-N were determined according to the methods of Zhang et al. (2020) (link) and Tu et al. (2010) (link). The COD concentration was determined using the acidic potassium dichromate oxidation method (HACH heating system, DR 900, DRB 200; HACH Co., Loveland, CO, USA); TN and TP concentrations were measured using the potassium persulfate digestion method; NO₃⁻-N and NO₂⁻-N concentrations were measured using the phenol disulfonic acid and Griess-Saltzman methods, respectively.
All data were analyzed by one-way analysis of variance (ANOVA) and presented as mean values ± SD (standard deviation). Significant differences in the means between treatments were determined by Duncan’s multiple range tests. Probabilities of P < 0.05 were considered significant. GraphPad Prism 8.0.2 and Origin 2019b were used to plot the data.

Sodium chlorite solution (450 mL of 10 μg/μL) was mixed with 1N hydrochloric acid (21 mL) in a 1000 mL PYREX^® storage bottle and stored for 1 h at room temperature with continuous stirring [28 (link),29 (link)]. The final working concentration of 5 ppm was prepared by diluting the stock solution with distilled water. The concentration was confirmed by direct-reading method (HACH DR 900, Loveland, CO, USA). The pH value of the ClO₂ solutions averaged at 8.67.

This research was conducted on a laboratory scale. The leachate samples were taken from the inlet of the leachate holding pond at the Griyomulyo Landfill, Jabon, Sidoarjo. The sampling location of leachate is shown in the supplementary data. In this study, the initial parameter analysis of leachate was chosen as a research variable based on the Quality Standards of the Minister of Environment Regulation No. 59 of 2016 and the USEPA International Quality Standards, namely Total Nitrogen (TN), Heavy Metals Cadmium (Cd) and Mercury (Hg), BOD, COD, TSS, and pH (USEPA, 2000). Total nitrogen (TN) and COD were analyzed using a colorimeter DR 900 (HACH, USA). Then, BOD was measured after five days of incubation at 20 °C with a DO meter DO-5510 (MRC). Subsequently, total suspended solids (TSSs) were determined using the gravimetric method, and pH was measured in situ using a portable ST300G (OHAUS). Meanwhile, for heavy metals, Cd was analyzed using Flame-AAS instrument based on SNI 6989–84:2019 standard method, and Hg analysis was based on SNI 6989–78:2019 with Cold Vapor AAS.

COD were determined using HACH color meter (DR900, USA) according to the manufacturer’s instructions. The pH was recorded using a pH analyzer (Agilent 3200 M, USA). TS and VS were determined based on the weighing method after being dried at 103–105 °C and burnt to ash at 550 °C. The CH₄ production was determined using a gas chromatograph (Clarus 580 Arnel, PerkinElmer, USA) equipped with a thermal conductivity detector. C, N, S and H elemental analyses in FW were determined using the vario MICRO cube (Elementar, HANAU, Germany). Metals elemental analyses were conducted using an inductively coupled plasma (ICP) – optical emission spectrometer (Perkin Elmer Optima 5300 V, USA). BET surface area and pore volume of activated carbons were measured by N2 adsorption measurement using a Quantachrome Autosorb-6B. Real-time PCR was used to quantify total archaea according to the methods described by Zhang et al.^{24 (link)}.